Search Publications

The neutron star mass and radius of Aql X‑1 from quiescent X‑ray emissions

Li, Z.; Luo, Y.

We report the quiescent spectra of neutron star (NS) in Aql X‑1 from XMM‑Newton and Chandra. The NS atmosphere model, NSATMOS, is applied to fit the quiescent spectra. The Monte Carlo Markov Chain algorithm is used to constrain the NS mass and radius in Aql X‑1. We find that the absolute flux calibration between XMM‑Newton and Chandra for Aql X‑1 …

Project BMK10k: Zeiss Ballistische Messkammer with a 10k × 10k CCD for ground‑based PLATO support

Chini, Rolf; Strassmeier, Klaus G.; Granzer, Thomas +5 more

Ballistische Messkammer with 10k CCD's (BMK10k) central goal is supporting the upcoming PLAnetary Transits and Oscillation of stars (PLATO) mission by reducing its number of false positives (planet‑compatible transit candidates but not planets at the end). For Kepler, the number of false positives had been estimated to still be about 10%. Understa…

A new method for extracting seismic indices and granulation parameters: Results for more than 20,000 CoRoT and Kepler red giants

Michel, E.; Samadi, R.; de Assis Peralta, R.

We have developed a new automated method intended to perform the simultaneous—and thus more consistent—measurement of both the seismic indices characterizing the oscillations and the parameters characterizing the granulation signature of red giant stars. This method, called MLEUP, takes advantage of the Maximum Likelihood Estimate (MLE) algorithm …

Photometric and spectral observations of two W UMa stars with periods of one third of a day

Kjurkchieva, D. P.; Marchev, D. V.; Popov, V. A.

Speckle observations with PISCO in Merate (Italy): XVI. Astrometric measurements of visual binaries in 2015, and new orbits for DUN 5, ADS 5958, 6276, 7294, 8211, and 13169

Scardia, M.; Prieur, J. -L.; Pansecchi, L. +3 more

We present relative astrometric measurements of visual binaries, made in 2015, with the speckle camera PISCO of the 102-cm Zeiss telescope of Brera Astronomical Observatory, Merate, Italy. Our observing list contains orbital couples as well as binaries whose motion is still uncertain. We obtained 196 new measurements of 173 visual binary stars, wi…

Spectral evolution of the two classical novae PW Vul and V1668 Cyg using International Ultraviolet Explorer low‑resolution spectra

Sanad, M. R.; Yousef, S.; Essam, A. +2 more

We studied the evolution of the normalized flux of selected ultraviolet (UV) emission lines of two classical novae (PW Vul and V1668 Cyg) using International Ultraviolet Explorer (IUE) short wavelength observations. Different phases of the outburst are studied. Emission lines covering a wide range of ionization states are investigated. We use the …

The first Charge Coupled Device photometry of the poorly studied clusters Teutsch 126 & Czernik 11

Hendy, Yasser; Tadross, Ashraf Latif; Bendary, Reda +1 more

In this study, we determined the astrophysical parameters of the poorly studied clusters Teutsch 126 and Czernik 11. We used the Visual Red Charge Coupled Device pass-bands that were carried down to a limiting magnitude of V = 20 mag. The stars of the clusters were observed utilizing the Newtonian focus of a 74-inch telescope at the Kottamia Astro…

A photometric study of the nonrelaxed cluster Mayer 3

Tadross, A. L.; Bendary, R.; Hasan, P.

The astrophysical parameters of the open star cluster Mayer 3 have been estimated using the Newtonian focus (f/4.84) of the 1.88 m Telescope of Kottamia Observatory in Egypt. The VRI observations have been carried out down to a limiting magnitude of V ~ 20 mag. To emphasize the main astrophysical parameters, Near-Infra Red, Two Micron All Sky Surv…

An analysis of four stellar rings

Leschinski, Kieran; Paunzen, Ernst; Gütl-Wallner, Anna +9 more

Athena: ESA's X-ray observatory for the late 2020s

Piro, L.; Nandra, K.; Barcons, X. +8 more

Observations of the X-ray sky after the next decade will most likely be dominated by Athena (Advanced Telescope for High ENergy Astrophysics), the second large mission of ESA's Cosmic Vision 2015-2035 programme. Athena has been conceived to address the "Hot and Energetic Universe" science theme, which focuses on the assembly and evolution of hot b…